Railway switch lamp



Sept. 1941- J. F. LINDBERG 2,257,175

. RAILWAY SWITCH LAMP Filed May 3, 1940 EVEN U.Z

Patented Sept. 30, 1941 UNITED STATE RAILWAY SVJIT CH LAMP John F. Lindberg, Chicago, 111., assignor to Carter Blatchford, Incorporated, Chicago, 111., a corporation of Illinois Application May 3, 1940, Serial No; 333,061

(Ci. 24ii22) 3 'Ciairns.

The present invention relates in general to light projecting and concentrating means and is more particularly concerned with an improved lamp construction which is especially adapted for projecting a plurality of light beams in angularly disposed directions.

The present invention is susceptible of multitudinous applications, but has been found to be particularly useful in connection with trafiic lights, railway switch lamps, and the like. I

Heretofore in switch lamps it has been the usual practice to provide a suitable lamp housing in which four main lenses were mounted with their primary or principal axes in quadrature.

A common light source, either oil or electric,-is i5 usually positioned in the housing at the junction of the primary axes of the lenses, these lenses being arranged to converge the light rays falling thereon into angularly disposed beams.

Since the main lenses are of circular construction, the edges of these lenses are spaced apart in the housing. 1

In such an arrangement a large amount of the light rays emanating from the light source impinges against the interior of the housing wall and is wasted, these rays failing to pass through the lenses. As a consequence the overall efiiciency of the lamp is materially decreased and full use is not made of the available light from the light source.

7 Moreover, with the advent of high speed trains it is of increasing importance from the standpoint of safety to utilize signal lamps having high visibility. Although such high visibility could be obtained by increasing the power of the light without having to increase the power consumed by the light source.

A further object of the presentinvention is to provide an improved light projection device,

wherein converging lenses are positioned proximate the light source for deflecting light rays which are normally wasted to the main lenses of the device.

A further object is to provide an improved device of the character described wherein the efilciency may be increased by means of a supplemental lens assembly which may be applied to existing devices irrespective of whether the light source is oil or electric, and when of the 'oil type will serve to form a chimney therefor.

A still further object of the invention is to provide an improved lens construction as an article of manufacture. I

Other objects and features of the invention will more fully appear from the following detailed description taken in connection with'the accompanying drawing which illustrates a single embodiment thereof, and in which:

Figure 1 is a side-elevational View of a switch signal standard having applied thereto a lamp embodying the features of construction of the present invention; 4

Figure 2 is a vertical sectional view through the lamp structure; and

Figure 3 i an enlarged horizontal sectional view through the lamp structure, showing the cooperative relationship of the lenses thereof, taken substantially on line III-III of Figure 2.

As shown on the drawing:

Referring to the illustrated embodiment of the present invention, there is disclosed in Figure 1 a railway switch standard It as usually provided in connection with railway switches, this standard being arranged to assume 90 angularly spaced positions depending upon whether the switch is open or closed. As is th usual practice, this standard is equipped with a semaphore Ii for indicating the switch position during the day time, and carries at its uppermost end a switch lamp as generally indicated at l2.

In the adaptation shown, the switch lamp includes a tubular body portion l3 provided with four openings through which light istransmitted. The openings are surrounded by cylinder or hood members hi which are joined at their innermost ends to the body. Each of the hoods, as indicated in Figures 2 and 3, are according to the usual practice fitted with a main len .l 5 for concentrating light rays from a light source substantial- 1y into a light beam. As disclosed in the drawing, this lens is of circular construction with a smooth spherical outer surface, and an inner surface having a series of concentrically arranged ridges or corrugations.

The opposed lenses arranged on opposite sides of the lamp body may be green, while the two lenses at right angles to the green lenses are usually red, so that when the switch is in one position the red lenses will be visible along the track, whereas when the switch is in the other direction the green lenses will be visible.

At the common foci of the main lenses, there is arranged a suitable light source, which light source may be either electric or oil, an oil burner I6 being shown in the present instance.

The switch lamp thus far described is the usual construction. It will benoted that in such construction, the edges of the main lenses are spaced apart and there is considerable space between the main lenses where light rays from the light source will fall without passing through the main lenses. It will therefore be obvious that the lamp is under such circumstances inefiicient and that full utilization of the available lightrays is not taken advantage of, the rays between the edges of the lenses being wasted and performing no useful purpose.

More specifically, as shown in Figure 3, the angle subtended by the lens in the usual constructions would be .;as ;defined%by the dot-dash linesp| 1- -l8 for each lens. In other words, these lines mark the boundary of the light rays which would pass directly intothe .main lens from the light source. It will therefore be evident that between the lines H and I8 of :each :lens and lines 1,9 'and ZU which are respectively drawn through the housing from the light source center with an angle :of 45 from the principal axis of the lens there is ,a considerable area in which light rays impinge against the housing and are wasted since these rays do ,not pass'through the main lenses. I r

The present invention contemplates auxiliary which may be utilized in the customary switch house construction for redirecting these wasted light rays so that they will pass through the mainlenses and-thus increase the efficiency and power of the switch lamp.

For such purpose I have associated with each of the main lenses an auxiliary lens 21 which is placedprox-imate to the light source between the main lens and its principal focus. Each auxiliary lens subtends an angle of 90, with 45 disposed on either side of the principal axis :of the lens. With this arrangement, the light rays emitted between lines 1-! and I8 and the lines I!) and 20 will be deflected :between the boundary lines '22 and 2:3 as shown by the. dash lines in Figure .3 so as to. pass through the main lens and not be wasted.

lenses 2! maybe separately constructed or may be molded as an integralunit. Each lens 2| will have the usual upper and lower circular edges as shown at 24 and '25 in Figure .2, but the horizontally opposed edges '26 and, 21, will be truncate and form straight edges Which are beveled at angle of 45 so that adjacent auxiliary lenses may be joined :at these truncate edges and when so joined will have their principal axes disposed in .90? relation coincident with the principal; axes of the main lenses.

The auxiliary lenses may have their truncate edgesjoined in any suitable manner by means of ahywellknown adhesive material suitable for such purpose. With the auxiliary lenses so assembled orwhen integrally formed, the lenses cooperate toieffect a chimney which may be utilized to house the flame of theoil burner, when 'an oil burner forms a part of the switch lamp.

The assembled lenses may be supported on a truncate conical structure as shown at 28 for holding the lenses in proper position. This structure may be provided with a plurality'of holes for admitting air, when the auxiliary or supplemental lense structure is utilized with an oil burner.

. From the foregoing description, it will be apparent that the present invention provides novel supplemental means for a switch lamp, whereby a large portion of the light rays which are now normally wasted may be utilized advantageously to increase the lamp efliciency without having to increase the power of the light source; which embodies an improved light projecting device wherein .converging lenses are positioned proximate the light source for deflecting light rays into the main lenses of the device; which provides an improved lens assembly which may be utilized with switch lamp devices irrespective of whether the lightsource is an oil burner or electriclam-p, and when the oil type will serve to form a chimney therefor; and which embodies an improved lensconstruction asan article of manufacture. I

It will, of course, be understood that various details of construction may be varied through a wide range without departing from, the principles of this invention, andit is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope and spirit-of the appended claims.

' I claim ;as my invention:

1. In a cruciform railway signal lamp formed .of a vertical tubular body having four side openings quadrature and having four horizontally and outwardly extending tubes aligned with the openings, a single main lens in each of said tubes and disposed spaced outwardly of the periphery of said body, alight source in said body at the center thereof, a vertical tubular lens structure removably placed about said source and defining a relatively short chimney therefor, said lens structure being formed of four auxiliary planoconvex lenses smaller than the main lenses and having their plane faces disposed to define a quadrangular chimney opening and having their convex faces in spaced opposed and focused relation to the main lenses, said auxiliary lenses'having their vertical edges beveled inwardly and secured to the meeting vertical edges of adjacent lenses.

'2. In a cruciform railway signal lamp formed of a vertical tubular body having four side openings in quadrature and having four horizontally and outwardly extending tubes aligned with the openings, a main lens in each of said tubes and disposed spaced outwardly of the periphery of said body, a lamp structure in said body at the center thereof and including a'base, an upstanding support on said base, a vertical tubular lens structure removably seated on said support and defining ar'elatively short chimney for said lamp structure, said lensstructure being formed of four auxiliaryiplano-convex le'n'ses smaller than the main lenses andh'aving their plane faces disposed to define a quadrangular'chimney opening and having their convex faces in spaced opposed and focused relation to themain lenses, said auxiliary lenses having their vertical edges beveled inwardly and secured to the meeting vertical edges of adjacent lenses.

3. In a cruciform railway signal lamp formed of a vertical tubular body having four side openings in quadrature and having four horizontally and outwardly extending tubes aligned with the openings, a single main lens in each of said tubes and disposed spaced outwardly of the periphery of said body, a lamp structure in said body at the center thereof, a vertical tubular lens structure removably seated on said lamp structure and defining a relatively short chimney therefor, said lens structure defining four plane-convex lenses smaller than the main lenses and having their plane faces meeting to define a quadrangular chimney opening and having their convex faces in spaced opposed and focused relation to said main lenses.

JOHN F. LINDBERG. 

